Search

Reduced order modeling (ROM) techniques are numerical methods that approximate the solution of parametric partial differential equation (PED) by properly combining the high-fidelity solutions of the problem obtained for several configurations, i.e. for several properly chosen values of the physical/geometrical parameters characterizing the problem. By starting from a database of high-fidelity solutions related to a certain values of the parameters, we apply the proper orthogonal decomposition with interpolation (PODI) and then reconstruct the variables of interest for new values of the parameters, i.e. different values from the ones included in the database. Furthermore, we present a preliminary web application through which one can run the ROM with a very user-friendly approach, without the need of having expertise in the numerical analysis and scientific computing field. The case study we have chosen to test the efficiency of our algorithm is represented by the aortic blood flow pattern in presence of a left ventricular (LVAD) assist device when varying the pump flow rate. [ABSTRACT FROM AUTHOR]

Aim: To reach a consensus on a consistent strategy to adopt when screening patients for dental/periodontal infections and on the feasibility of providing dental treatment before cardiothoracic surgery, cardiovascular surgery or other cardiovascular invasive procedures. Methodology: A panel of experts from six Italian scientific societies was created. The deliberations of the panel were based on the RAND method. From an initial systematic literature review, it became clear that a consensually validated protocol for the reproducible dental screening of patients awaiting cardiac interventions was considered mandatory by professionals with expertise in the dental, cardiologic and cardiac surgery areas. However, a systematic review also concluded that the treatment options to be provided, their prognosis and timing in relation to the physical condition of patients, had never been defined. Following the systematic review, several fundamental questions were generated. The panel was divided into two working groups each of which produced documents that addressed the topic and which were subsequently used to generate a questionnaire. Each member of the panel completed the questionnaire independently, and then, a panel discussion was held to reach a consensus on how best to manage patients with dental/periodontal infections who were awaiting invasive cardiac procedures. Results: A high level of agreement was reached regarding all the items on the questionnaire, and each of the clinical questions formulated were answered. Three tables were created which can be used to generate a useful tool to provide standardized dental/periodontal screening of patients undergoing elective cardiovascular interventions and to summarize both the possible oral and cardiovascular conditions of the patient and the timing available for the procedures considered. Conclusions: Upon publication of this consensus document, the dissemination of the information to a wide dental and cardiac audience should commence. The authors hope that this consensus will become a model for the development of a dedicated protocol, ideally usable by heart and dental teams in the pre‐interventional preparation phase. [ABSTRACT FROM AUTHOR]

Copyright of Herz is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many recent studies on water have conjectured a complex structure composed of hydrogen bonded low- and high-density domains. In this work the structure of pure water and aqueous solutions of silica gel (TEOS) has been investigated by using delayed luminescence, which has previously shown a significant increase in aqueous salt solutions where low-density domain formation is expected. Photon emission shows an Arrhenius trend with an activation energy in water–TEOS solutions larger than in pure water and salt-water solutions. Moreover, delayed photon emission decay shows an intrinsic lifetime of about 5 μs both in solutions and in pure water that, along with secondary lifetimes induced by the presence of TEOS, could be related to the formation of different domains. [ABSTRACT FROM AUTHOR]

Introduction: Currently, chronic kidney disease (CKD) is a major health problem and in the most severe conditions, kidney transplantation is an alternative treatment. However immunosuppression induced these patients to respiratory complications and endotracheal intubation. In order to assist the decision of the best time for weaning and extubation of these patients, there are predictive indexes that should be considered in preliminary assesment. Objective: To check the capacity of predictive indexes for weaning of mechanical ventilation, rapid shallow breathing index (RSBI), oxygenation rate (PaO2/FiO2) and maximum inspiratory pressure (MIP) in predicting the success or extubation failure in kidney transplant patients. Methods: This study is a prospective cohort carried out with patients aged over 18, under mechanical ventilation for more than 24 hours. The patients were submitted to the Spontaneous Breathing Test, also the assessment of the Rapid Shallow Breathing Index, oxygenation index (PaO2/FiO2), and maximum inspiratory pressure (MIP) and they were observed during 48 hours after to evaluate the success and extubation failure. Results: A total of 106 patients were eligible, and 20 of these were included with mean age of 46.9 ± 3.06 years and 14 of the subjects were male. Three patients showed extubation failure, and needed to have reintubation within the period of 48 hours as considered. Conclusion: The indices to predict weaning of mechanical ventilation, when within the expected normal values, seem to be able to predict extubation, with the exception of MIP that, even in cases of success, showed itself to be at levels lower than the predicted percentage. [ABSTRACT FROM AUTHOR]

A spectrometer to detect the ultra-weak luminescence originated by the collision of cluster ions on the surfaces of solid materials was constructed. This spectrometer consists of 11 photomultipliers with band-pass interference filters that can detect the luminescence within the wavelength ranging from 300 to 700 nm and of a photomultiplier without filter. The calibration of the detection system was performed using the photons emitted from a strontium aluminate fluorescent tape and from a high temperature tungsten filament. Preliminary measurements show the ability of this spectrometer to detect the cluster ion beam induced luminescence. [ABSTRACT FROM AUTHOR]

Copyright of Herz is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Decreasing the Internet power consumption is a challenging issue. Optical transport networks employing the wavelength division multiplexing (WDM) technique have been identified as energy efficient solutions to face this issue, considering the expected high increase of Internet traffic. The authors study the energy efficiency of a recently-proposed switching technique for transport networks, the time-driven-switching (TDS), in which time-coordination of network elements is exploited to achieve 'sub-lambda' granularity in optical signal switching directly in the optical domain. In order to achieve the fast switching time required by TDS, semi-conductor optical amplifier-based optical switches are exploited. The authors discuss the properties, in terms of the energy efficiency, of a TDS transport network, focusing on the energy requirements of the TDS optical switches. The authors provide a qualitative description of the main contributors to energy consumption in a TDS network. The authors then develop an integer linear programming formulation, in which the physical impairments impact over optical signals is also considered. Power consumption over realistic case study networks for the TDS case is compared to the power consumption for the classical IP over WDM architecture, and in some cases TDS is demonstrated to save more than 55% of power consumption with respect to competing architectures. [ABSTRACT FROM AUTHOR]

Copyright of La Radiologia Medica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of La Radiologia Medica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At temperatures and densities that are typical of plasmas produced by lasers pulses interacting with solid targets, at power intensities I > 1012W/cm2, the classical Debye screening factor in nuclear reactions becomes comparable with the one of the solar core. Preliminary calculations about the total number of fusion reactions have been performed following an hydrodynamical approach for the description of the plasma dynamics. This approach is propaedeutic for future measurements of D-D fusion reaction rates. [ABSTRACT FROM PUBLISHER]

The modeling of laser-generated plasmas can be carried out by means of different theoretical approaches. Hydrodynamic simulations have the advantage of treating the plasma as a continuous fluid that expands in vacuum with a high Mach number. We used the analytical Anisimov model for the numerical simulations of a plasma expanding at supersonic velocities. The model describes the plume by means of a special solution of the gas dynamical equations on the hypothesis that the flow expands adiabatically. Here, we carry out a comparative analysis between experimental and numerical results: the model fits the experimental data for monoatomic plumes quite well. More specifically, the numerical data have been tested by comparing the time-of-flight signals obtained at the INFN-LNS in Catania from a pure metallic target. A Coulomb drift velocity was added to the expansion velocity, and only in this way was it possible to explain the experimental results, thus confirming the presence of self-generated electrostatic fields inside the expanding plasma plume. [ABSTRACT FROM AUTHOR]

Laser-generated plasmas, formed when a high power pulsed laser is focused onto a solid target, have been used since the 1960s. At higher power densities (>109-1010 W/cm2), such non-equilibrium plasmas expand in vacuum with supersonic velocities. Hydrodynamic simulations and experimental data show that at the beginning of the expansion the plasma temperature may reach several hundreds of eV, while the density is in the order of 1016 cm-3 or higher. Colliding laser-produced plasmas have constituted a largely unexplored and unexploited research domain until quite recent times, either for applications in materials or energy science. In this article, we propose the use of colliding laser-produced plasmas as an unique opportunity for nuclear astrophysics studies. We present a series of calculations about fusion reaction rates in laser-produced plasmas where the electron screening puzzle is taken into account. The numerical simulations have been carried out using the hydro code ZEUSMP2, while Monte Carlo codes have been used to simulate the fusion reaction rates according to the plume density and temperature evolution predicted by the simulations. We think that this type of investigation can be important in understanding the efficiency of nuclear reaction rates during the red giant phase of stellar evolution, as a significant part of the produced energy is dissipated in the low-density radiative envelope by shock waves. [ABSTRACT FROM AUTHOR]

Design and characterization of a new generation of single-photon avalanche diodes (SPAD) array, manufactured by ST-Microelectronics in Catania, Italy, are presented. Device performances, investigated in several experimental conditions and here reported, demonstrate their suitability in many applications. SPADs are thin p-n junctions operating above the breakdown condition in Geiger mode at low voltage. In this regime a single charged carrier injected into the depleted layer can trigger a self-sustaining avalanche, originating a detectable signal. Dark counting rate at room temperature is down to 10 s-1 for devices with an active area of 10 mum in diameter, and 103 s-1 for those 50 mum wide. SPAD quantum efficiency, measured in the range 350-1050 nm, can be comparable to that of a typical silicon based detector and reaches the values of about 50% at 550 nm. Finally, the low production costs and the integration possibility are other favorable features in sight of highly dense integrated 1-D or 2-D arrays. [ABSTRACT FROM PUBLISHER]

Optical spectroscopy is an effective tool to explore the laser-produced plasma. The complex interaction processes occurring in the plasma could be, in principle, analysed using time-resolved studies of its spectral emission. Nevertheless, it is difficult to realize this possibility due to the inadequacy of currently available photon detectors, as photomultipliers or change-coupled devices, which does not have enough time resolution and are not rugged enough to be used in applications in which very high intensity pulses of visible light are produced. To explore new solutions, two prototypic arrays of single photon avalanche diodes obtained by ST-microelectronics, working in silicon photomultiplier configuration, have been used to obtain information on the space and time evolution of a plasma plume generated by a 500 mJ Nd:YAG laser at 1064 nm wavelength and 9 ns pulse duration. The obtained results are shown and the further potentialities of these detectors in this field are discussed. [ABSTRACT FROM AUTHOR]

This study aims at proving that single photon sensing can be made accessible in the form of cheap off-the-shelf micro-devices with micro-optical/micro-mechanical coupling systems. In order to achieve this challenging goal, use is made of different micro-technologies, not yet fully established but promising and innovative in and of themselves. It is planned to combine them into a more challenging micro-technology capable of making single photon handling off-the-shelf. Moreover, the technology to be implemented should make it possible to provide photonic sensors in a ready-to-go fashion. [ABSTRACT FROM AUTHOR]

We outline the possible applications of newly developed single photon avalanche detectors (SPAD) operating at low voltage and fabricated in silicon planar technology, reporting on tests done with scintillators. We envisage the integration of large arrays of identical sensors, employing a common read-out mode in order to achieve a high resolution and high sensitivity solid state photomultiplier. The applications of such a device would be many, particularly if we consider that we are also working on the production of microoptical components, perfectly suited for the lossless coupling of these photosensors to several light sources (lasers, ordinary and scintillating fibers, scintillators, optical devices), by exploiting the promising deep lithography with ions (DLI) technology. Crossed time-of-flight and charge measurements between SPADs and usual photomultipliers, coupled to scintillators, have allowed to compare their relative performance. Specific issues regarding the SPAD and the scintillating fiber readout are presented, also in view of possible applications in the field of particle/radiation tracking systems [ABSTRACT FROM PUBLISHER]

Abstract: In order to investigate the role of water network in collagen structure, measurement of dielectric permittivity was performed on bovine Achilles’ tendon as a function of water content. The data show a sudden decrease of the permittivity at each measured frequency value when the tendon humidity decreases. A similar behaviour is shown by the total number of photons emitted in delayed luminescence (DL) experiments. The comparison of the two results is in agreement with the hypothesis that DL is connected to the excitation and subsequent decay of collective electronic states, whose properties depend on the organized structure of the system. [Copyright &y& Elsevier]

This article describes new advanced research equipment for fast ultraweak luminescence analysis, which can detect at high sensitivity photons after ultraviolet A laser irradiation in biological probes as well as plant, animal, and human cells. The design and construction of this equipment, developed at the Southern National Laboratory of the National Nuclear Physics Institute, is described with the first experimental results and future developments. The setup, employing a photomultiplier tube working in single photon counting mode, allows accurate and reliable photoluminescence measurements with excitation wavelengths in the range 337–700 nm and the emission wavelength in the range 400–800 nm. With respect to the traditional setup, this new equipment is able to perform measurements starting at a few microseconds after the laser irradiation is switched off and with a large detection efficiency (about 10% of the total solid angle). Moreover, the adopted design assures a low background noise level. A further optimization of the system is under study, with special care for the reliability needed for the delayed luminescence for optical screening project aimed to enhance the detection of the low level photoinduced luminescence from human cells to be used as an optical biopsy technique. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Copyright of Il Nuovo Cimento della Societa Italiana di Fisica: D is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Il Nuovo Cimento: C is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Il Nuovo Cimento: C is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The solar contribution to space heating and cooling is evaluated through an analytical procedure. The method used simulates the building as a thermal network in which each node corresponds to the centre of a room and each mesh arm to a wall; building materials and frames are explicitly taken into account. The network is excited by a set of generators corresponding to external excitations ( e.g. environmental temperature, solar flux, etc.) which are described by a truncated Fourier series. The network is resolved by an analytical method through the matrix formalism and gives either the time diagrams of indoor temperatures in each room, or the diagrams of the auxiliary energy required to maintain a set room temperature. The application to a residential environment is presented as an example and is discussed in relation to a passive retrofitting design. The results are briefly compared with those obtained through established procedures, to give evidence of the occurrence of strong fluctuations on the average values which significantly influence the conditions of comfort. The method can be implemented at the level of microcomputers. [ABSTRACT FROM AUTHOR]

Copyright of Il Nuovo Cimento: C is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Forty-four consecutive infants aged from 3 days to 10 months underwent repair of total anomalous pulmonary venous connection using deep hypothermia with circulatory arrest. There were eight (18%) early hospital deaths. Using multivariate analysis no significant association could be shown between early mortality and age or weight at operation, preoperative pulmonary or systemic pressure, and preoperative condition for patients undergoing operation during the most recent five year period. Late pulmonary venous obstruction developed in four (11%) of the survivors and all of these patients died. [ABSTRACT FROM PUBLISHER]

Between January 1974 and November 1980, 13 symptomatic infants under 1 year of age with persistent truncus arteriosus type I or II underwent surgery. Pulmonary artery banding was performed in 10 cases, with five deaths. Among the survivors, one developed severe pulmonary vascular disease and only two underwent late intracardiac repair. Primary total correction was performed in three infants and all are well, though one required conduit replacement five and a half years after the initial procedure. Recently, antibiotic sterilised homograft conduits, rather than heterografts, have been preferred as extracardiac conduits in infancy. Early intracardiac repair followed, if necessary, by later conduit replacement appears to have significant advantages over "conventional" pulmonary artery banding and late total correction. Concern remains on the treatment of choice in infants under 3 months of age. [ABSTRACT FROM PUBLISHER]

Soft-X-rays irradiation of yeast cells allows selective interference with different cellular structures. The monitoring of different physical parameters leads to substantial variations in the response to X-rays showing that monotonicity should not be taken for granted. [ABSTRACT FROM AUTHOR]